Final answer:
The sequence is geometric with a common ratio of -7.
Step-by-step explanation:
The question asks whether the sequence is geometric and if so, to find the common ratio.
An example of a geometric sequence is one in which each term is obtained by multiplying the previous term by a constant ratio. For a geometric sequence, the ratio between consecutive terms remains constant.
Given the options provided, the correct answer is c) Geometric; common ratio: -7. In this case, each term in the sequence is obtained by multiplying the previous term by -7, thus forming a geometric sequence.